1. Field of the Invention
This invention relates to mouthguards and particularly to mouthguards adapted for minimizing shock to the teeth and head area.
2. Description of the Prior Art
There are a number of different types of mouthguards presently available on the market but they have deficiencies which prevent their giving optimum protection to the wearer against serious injuries to the teeth and particularly to the head and neck area.
For example, many mouthguards consist simply of U-shaped trough-like members of resilient material, such as rubber or suitable plastic, shaped to fit over the upper or lower teeth or both. In the case of many such mouthguards, a blow to the lower jaw may result in one or more teeth penetrating through the mouthguard structure and, more importantly, such mouthguards provide little, if any, protection against head and neck injuries.
One prior art mouthguard is formed to provide a bottom wall which increases in thickness from the posterior to the anterior area, this increase in thickness being such as to conform to the normal angle of approach of the upper and lower jaws in the act of closing the mouth and thereby to ensure engagement of the mouthguard by the incisors of the lower jaw simultaneously with the molars thereof. Because of the construction and hinging of the lower jaw, the movement of the forward portion thereof relative to the rear portion during opening and closing of the mouth is approximately a three-to-one ratio. This prior art structure is apparently intended to have a gradually increasing thickness toward the forward portion so as to correspond generally to this ratio and to thereby provide an even distribution of contact over all the teeth. As will be explained later in describing the invention of the present application, this even distribution of contact cannot accomplish the beneficial results of the applicant's invention.
Another prior art structure involves a mouthpiece with a triangular-shaped ridge depending from the lower wall thereof in the molar-bicuspid area. In this structure, the depending ridge has a relatively sharp edge which is intended to engage the lower teeth in the central area between the buccal and lingual cusps, that is, in the fossa of the lower teeth. In the case of this structure, as the triangular ridge is compressed as a result of a blow to the lower jaw, it spreads somewhat against the sides of the cusps, creating an undesirable lateral force. Moreover, in the case of many individuals, the teeth are not in direct line and the straight edge of the ridge in that case would engage not the fossa but the inner or outer inclined walls of the cusps, depending on the direction of misalignment of each individual tooth, again creating undesirable lateral force and defeating the purpose of the mouthguard.
Normally, the head of the condyle of the mandible articulates with a cartilagenous disk or movable cartilagenous pad in the temporomandibular joint, and it is this pad which glides between the condylar head of the mandible and the articular surface of the glenoid fossa of the temporal bone. In wearing conventional mouthguards, the athlete is not only subject to potential damage to the teeth but, more importantly, to damage resulting from direct transmittal of force through the mandible, the thin layer of cartilage, and into the temporal bone and the cranial cavity. Substantial increases in intracranial pressure and cranial bone deformation have been shown to occur when a football player, for example, receives a blow on the chin or on the faceguard of the protective helmet. This results in a measurable deformation of the skull. Similar damage occurs in other contact sports, such as, boxing, hockey, soccer, lacrosse, etc. Because of the use of protective helmets with faceguards for intercepting horizontal blows, the principal injuries to football players in the head area result from upward blows to the lower jaw, especially the chin area, and upward blows to the faceguard which transmit force to the jaw through the chin strap.
By the present invention these limitations and deficiencies of the prior art mouthguards have been overcome and not only is protection provided against damage to the teeth, but the mouthguard is constructed so as to provide an increased separation between the mandible and the glenoid fossa and to slightly increase this separation in the case of a blow to the chin or faceguard and thereby to avoid transmission of damaging force from the condyle of the mandible to the temporal bone and the cranium.
Accordingly, it is a primary object of the present invention to provide a protective mouthguard designed to provide an orthopedic placement of the mandible relative to the cranium and, more specifically, relative to the glenoid fossa of the temporal bone with which it articulates.
It is a further object of this invention to provide not only a cushioning against upward forces but also to provide a pivoting action about a fulcrum point in the molar area to cause a slight rocking shock absorption motion.
It is a further object of this invention to minimize stresses to the incisor teeth and to provide for easier breathing and speaking while wearing the mouthguard.
It is still another object of this invention to provide a mouthguard which functions effectively despite irregularities in the upper dental arch and in the plane of occlusion between the upper and lower jaws and teeth.
It is still a further object of this invention to provide a mouthguard in a limited number of sizes which are suitable for fitting substantially all mouth sizes and teeth characteristics and which may be fitted by the athlete without the necessity of custom-fitting by a dentist.
It is another object of this invention to provide a mouthguard which may be standardized in a limited number of sizes for commercial production and economically produced.
It is a further object of this invention to provide a mouthguard which will protect the temporomandibular joint against trauma.